Heat pumps · Error codes · Worcester Bosch
1038Worcester Bosch · Bosch Compress 5800i AW (R290 monobloc)
1038 on a Worcester Bosch Bosch Compress 5800i AW: Time/date invalid value
Short answer
On a Worcester Bosch heat pump, 1038 means: Time/date invalid value. The heat pump keeps running. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Time/date invalid value.
Part involved: real-time clock.
When it shows: Time/date invalid value.
Likely causes:
- Date/time not set; prolonged power loss.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
Resetting itself: Clears when cause removed.
Manual reset: Reset/acknowledge via UI 800 fault menu after cause removed.
What you can check
- Read and note the full code (and sub-code) shown on the controller and pass it to your installer.
- Check thermostat / time program / operating mode settings on the controller.
What the engineer will check
- Set date/time.
Who to ask for: heat pump installer / controls engineer.
Certification: None specific; electrical isolation required before wiring checks.
What you might notice
What owners and engineers report
1 owner and engineer report mentions this.
- Controller / thermostat problem on the Bosch Compress 5800i AW (R290 monobloc): 1 report
Sources
- Installationsanleitung Bedienfeld UI 800 (Luft-Wasser-Wärmepumpe) 6721833375 ↗ · 6721833375 (2023/09) DE, AT, CH, LU · page 21 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026